Water Adsorption and Decomposition on N/V-Doped Anatase TiO2 (101) Surfaces

With use of the generalized gradient approximation within density functional theory approach combined with periodic slab models, the adsorption and decomposition behaviors of water molecule on N/V-monodoped, and N-V-codoped anatase TiO2 (101) surfaces at gas ambient were studied. By optimizing the geometrical configurations of initial molecular adsorption states, transition states, and final dissociative adsorption states, the adsorption energy of each species and the reaction activation energy data on the reaction pathways were obtained. On N-doped surface, the decomposition reaction pathway of water is changed: the activation energy is reduced and the decomposition reaction is an exothermic reaction, which is favorable for the decomposition of water. On the other hand, V-doped surface is unfavorable for water decomposition. The decomposition reaction of water on the N-V-codoped surface is a structure-sensitive reaction process, i.e., it has a completely different reaction activity on the different surface positions. Due to N-V codoping promoting the generation of surface oxygen vacancies, the adsorption and decomposition behavior of water on TiO2 (101) surface containing oxygen vacancy was also considered, on which the water molecule could be easily decomposed, forming two stable surface-terminated hydroxyl radicals.